Process of preparing materials for briquetting and the product thereof



Sept. 1, 1925. 1,551,966

P C. MULLIGAN ET AL PROCESS OF PREPARING MATERIALS FOR BRIQUETTING ANDTHE PRODUCT THEREOF Filed Nov. 14, 5

gwue'n tow Mvd elk-bounty!) Patented Sept. 1, 1925.

UNITED STATES 1,551,966 PATENT OFFICE.

PAUL C. MULLIGAN AND HERBERT G. SWALWELL, SEATTLE, WASHINGTON, AS-

SIGNORS TO THEMSELVES, LUTHER J. HULL, AND ISAAC M. FOSTER, ALL OF SE-ATTLE, WASHINGTQN.

PROCESS OF PREPARING MATERIALS FOR BRIQUETTTNG AND THE PRODUCT THEREOF,

Application filed November 14, 1923. Serial No. 674,704.

To all whom it may concern:

Be it known that we, PAUL C. MULLIGAN and HERBERT G. SWALWELL, citizensof the United States of America, and residents of the city of Seattle,in the county of King and State of Washington, have invented certain newand useful Improvements in Processes of Preparing Materials forBriquetting and the Product Thereof, of which the following is aspecification.

Our invention relates to the art of briquetting, and particularly to thepreparation of materials for briquetting.

Our invention is more especially designed *7 for the utilization ofwaste products such as saw dust or wood chips, and will be describedwith particular relation thereto. However, in the followingspecification and in the claims terminating the same, it will beunderstood that the term granular material is intended to apply eitherto saw dust or to wood chips in the natural state, or dried or charred,and either separated or in combination, or to other combustible matterin a divided form, which it is desired to finally compress into the formof a briquet.

One of our principal objects is the provision of a process whereby suchgranular materials may be prepared for briquetting through the use of asolid binder which may be supplied in a pulverized form and withoutheating, rather than in a liquid form, as has been customary heretofore,rendering it possible to employ an air current for handling thispulverized binder, and making it possible also to employ a simple beatertype of pulverizer for the pulverizatio-n of such solid binder Withoutdanger of fouling the screens employed in such a pulverizer.

A further object is the provision of a process for the preparation ofmaterials for briquetting, whereby the fuel value and the amount offlame-producing volatiles in the final briquet may be increased by theaddition thereto of a liquid hydrocarbon, as fuel oil, in such a mannerthat it will remain in the briquet and will not exude theligfrom orrender the briquet moist or stic A further object is the provision af aprocess for preparing materials for briquetting, which may be carried oncontinuously,

without interruption, to the end that the dentally with the presentapplication, yet it will be understood that the use of this particularpiece of apparatus is not essential to the process, nor in fact, is itessentialthat any particular form of apparatus be employed in carryingout the same. The apparatus which we have illustrated diagrammaticallyin the accompanying drawings represents only a form which mightconveniently be employed in carrying out the process.

Our invention comprises the novel steps, combinations and arrangementsthereof in the process of preparing materials for briquetting, and inthe novel mixture for briquetting and the novel briquet formed from suchmixture, all as disclosed in this specification and in the claimsterminating the same.

I Figure 1 represents diagrammatically a complete plant for the carryingout of our process of briquetting.

Figure 2 represents a transverse section through a beater type ofpulverizer, illustrating a form which may conveniently be employed incarrying out our process, al.

though it will be understood that the use of this particular type ofapparatus is not essential.

As we have stated above the base material which is in granular form,will preferably be carbonized wood saw-dust or chips. The saw-dust isgenerally considered a Waste product and it is to utilize this wastethat our process is particularly intended.- It should be understood,however, that we do not consider thatour process is limited only to theutilization of such materials, and in fact, .we have found it adaptableto the briquetting of such materials as .ordmary ground charcoal orcoal. Also wemay wish to utilize other combustible materlals which areordinarily wasted, and for that reason have chosen the term granularmaterial, as representing a material or several materials in granularform, generally of vegetable origin, and combustible, which it isdesired to incorporate into a briquet as the base thereof. a

The material, if saw-dust or chlps or like material is used, is. firstdried. We have shown in the drawings no means of drying the granularmaterial, nor in fact, do we consider this strictly a part of ourprocess, but merely a preliminary step which must be taken if thematerial requires it. Preferably the material is dried to the point ofcharring. After drying the material may be stored in a convenient place,as in a storage bin 1, from which it is fed as required into the hopper20 of a mixing chamber 2. As it enters the chamber 2 a liquidhydrocarbon, as, for example, fuel oil,- may be sup-' plied thereto. Theoil is supplied for the purpose of adding volatile matter to thebriquet, and its use for some briquets may be dispensed with, althoughpreferably it is employed.

The oil we have shown as being supplied from a tank 3 by means of aconduit 30, and we have shown a conduit for air which is contained in aholder 4 under pressure, which also communicates at 31 to a spray nozzlewith which the oil conduit 30 is connected. By this means .the oil, thesupply of which may be controlled, as by a valve 82,

is sprayed into and upon the granular material as it enters the mixingchamber 2. The oil and dry granular material are suitably mixed, as by ascrew 21 within the chamber '2, and finally when the mixing hasprogressed sufficiently that the oil impregnates the dry granularmaterial, the oil-moistened granular material is delivered to a secondmixing chamber 5.

During the time that the oil and granular material are being mixed, abinder therefor, which preferably consists, simply of normally solidasphalt, isbeing prepared for mixture therewith. In the drawings 60represents the casing of a common beater type pulverizer. In suchapulverizer, beaters 6 of hard metal are pivoted upon the ends of arms61, which in turn arepivoted upon a rotatable hub 62. Material to bepulverized is fed into a hopper 63 atthe top of the casing 60 and as thebeaters 6 rotate close to the interior of the casing 60, the solidmaterials are pulverized and finally dropped through a screen 64 formingthe bottom ofthrough aseparator 68 with the'chamber 5.

The pulverized asphalt enters the chamber 5 at substantially the samepoint as the oilmoistened granular material, and preferably is carriedthence by an air current from the blower 66. The pulverized material isdeposited upon the moist granular material and the air which serves as avehicle therefor 'passes through the chamber 5, which should be closed,and during its passage the air is relieved of all of the pulverizedmaterial. It is permitted to escape through a screened opening 50.

'lVithin the chamber 5 the pulverized binder and the g anular base arethoroughly mixed to disseminate the binder throughout the mixture. Thismay be done by means of a second screw conveyor 51 within the chamber 5.I The material is then ready for briquetting and may be delivered fromthe chamber 5 continuously into a hopper 7 3 of a briquetting press,indicated in general by the numeral 7 which, operating continuously,will produce briquets from the material thus prepared. For. conveniencewe have shown the briquetting press 7 as containing a cylinder 7 0 inwhich, by means of a piston, not shown, it is possible to compress airto be delivered through a conduit 74 to the air storage tank 4.

It has heretofore been considered impossible to use asphalt as a binderfor briquetting in the solid form, and without heating. This has beenfor the reason that the asphalt has always tended to clog the screens ofpulverizers employed to reduce it to a powdered form. We havediscovered, however, that by means of the addition to the pulverizer 60of a more friable material as, for instance, charcoal or coal, in aboutthe same or slightly greater amounts by weight than the asphalt, butperhaps twice the bulk thereof, it is possible to pulverize the asphaltand the friable material in conjunction with each other, and thereby torender the particles of asphalt so much less sticky than they normallywould be that there will be no tendency to clog the screens, as 64. Theaction appears to be that the friable material, being most readilybrokenup, has a portion pulverized first, before any pulverization ofthe asphalt begins. The particles of the friable material, then act tocoat the asphalt and to coatthe particles thereof as formed in suchmanner that the stickiness of the asphalt is removed, or the asphaltparticles are enclosed within a casing of fine particles of the friablematerial and thus do not cohere into a mass nor adhere to the screensurface. This renders it possible to use this simple and convenient typeof pulverizer as described and renders it possible also to convey thepulverized material by means of an any tendency for the asphalt to stickin any part of the apparatus employed.

A number of different materials may be used to prevent stickiness of.the asphalt binder. We have mentioned coal and charcoal as beingsuitable for such use, and prefer to use them for the reason that thesematerials are combustible as is the asphalt,

thus rendering the entire briquet combustible. It should be understood,however, that we do not limit ourselves strictly to the use of these twomaterials as a vehicle or separator for the asphalt particles, butprefer them on account of their combustibility. When other materials arethus employed, the amount employed is determined chiefly by their bulk,sufficient friable material being used to properly coat and separate thebinder and its particles in the manner described above.

As a substitute for asphalt we have used other solid binder materials,for example, pitch, both coal tar pitch and resins. We do not wish to belimited, therefore, solely to the use of asphalt as a binder. When pitchis employed, it is still desirable to employ charcoal or the like as aseparating medium for the individual particles of the binder material,andto pulverize the charcoal and binder materials together. Thecharcoal, in this capacity, acts to separate the individual binderparticles, to permit handling and to prevent reaccumulatlon thereof.

In brief, then, the complete process consists of the im regnation of thegranular base with a liquid hydrocarbon, coincidentally with whichimpregnation there is a pulverization of the asphalt and of charcoal .toform a combustible carbon carrier or separator therefor, followin whichthe pulverized materials and the oil-moistened granular materials aremixed thoroughly. The final mixture is then ready to be supplied to asuitable press and upon compression a briquet is formed, which is dr notsticky, which is fairly hard, and whic will not break down whileburning.

In compressing the briquetting mixture which we have described, theincreased density caused by compression appears to be suflicientto bringthe particles of the sticky asphalt binder closely enough together tocause cohesion ofall the granular particles, and as well, of the.pulverized carbon which has been put into the mixture with thepulverized asphalt.

It is difficult to express the proportions of the ingredients in such .amixture and in the briquet formed therefrom, with any exactness, for thereason that these percentages will vary considerably under varyingconditions. For example, the amount of fuel oil will be determinedprincipally by the absorption of the granular base and this in turn willvary with the character of the granular material, whether coal, charcoalor wood, and with the dryness thereof. Gen- "erally speaking, we mayemploy from 2% to 30% of fuel oil or its equivalent, althoughgenerallyin the neighborhood of 16% or' 17 is most desirable. Of theasphalt hinder, the amount will vary with the pressure employed in thebriquetting press, and also it will depend to some extent on the amountof fuel oil employed, a greater amount of fuel oil tending to keep thegranules of the base material separate and requiring a slightly greateramount of binder. Generally speaking, from 7% to 15% of the asphaltbinder will be employed under different conditions, with the preferredamount about 11%, when using carbonized saw-dust and fuel oil as theother constituents. The remainder (with the exception of the amount ofcarbon which is added with the pulverized asphalt, the per-- centage ofthis being substantially the same as of asphalt) will be the ranularbase. This, as stated above, might be charcoal or coal or such materialin combination with saw-dust or wood chips. Granular charcoal, includingthat introduced into the mixture with the asphalt, may be empolyed in anamount .necessary tocomplete the mixture, and preferablyshould bepresent in an amount approximatel 73% of the weight moistened base, andfinally mixing them to disseminate the binder throughout the mixture.

2. A continuous process of preparing fuels for briquetting whichconsists in pulverizing an asphalt binder in conjunction with carbon, atthe same time impregnating charcoal with fuel oil, introducing thepulverized materials by an air current to the oiled charcoal, wherebythe pulverized material is deposited, and then mixing the pulverizedmaterial and charcoal to disseminate the former throughout the mixture,i

3. A continuous process for the formation of a fuel briquet whichconsists in pulverizing a combustible binder in the cold state, inmixing a granular base material with said pulverized binder todisseminate the binder throughout the mixture, and finally com.-pressing it while cold to cause adhesion of the particles.

4. The process of pre aring fuels for briquetting with a norma y solidbinder material which consists in pulverizing the binder material inconjunction with carbon, in delivering the pulverized materials to agranular base by means of an air current, the granular base having beenmoistened by oil just cold and in its normal solid state, together witha more friable material, mixing the pulverized materials with a briquetbase, and

compressing the mixture while cold to cause the particles to cohere.

6. A briquetting mixture comprising a granular combustible baseimpregnated with oil, and a combustible binder in pulverized formthoroughly mixed therewith.

7 A briquetting mixture comprising a granular combustible baseimpregnated with a li uid hydrocarbon, and a pulverized combustlblebinder commingled with a pulverized combustible vehicle therefor, andthoroughlX mixed with the base.

8. briquet comprising fuel oil, an asphalt binder, a quantity ofpulverized carbon, and the remainder charred wood sawdust or chips, theamount of oil being limited by the absorption of the charred wood, the

quantity of carbon being suflicient to retain the asphalt in a ulverizedcondition until compressed, and t 1e quantity of binder being sufiicientto cause cohesion of the charred wood (particles when the mixture iscompresse 9. A briquet com rising fuel oil from 2% to 30% by weight,etween 7% and 15% of asphalt binder and the remainder a combustible base1n finely divided form, the amount of fuel oil being in any referredproportion up to the limit of a sorption thereof b the base, and thepercentage of binder being sufficient to cause the.o1l impregnatedparticles of the base to cohere when compressed.

10. A briquet including fuel oil approximately 16% or 17 by weight,about 11% of asphalt binder, and the remainder a granular combustiblebase.

11. A briquet containing the ingredients in substantially thepercentages by weight named, as fol ows: fuel oil, 16%, asphalt binder,11%, and carbon 73% in granular and pulverized form.

Signed at Seattle King County, Washington, this 2nd day of November1923.

PAUL O. MULLIGAN. HERBERT G. SWALWELL.

